A new analysis of a previous clinical study has found that Lipitor is more effective than Zocor in helping recent heart-attack patients cut their chances of having another attack. Patients in the study who took 80 mg of Lipitor reduced their risk of another heart attack by 46 percent compared to patients who took 20 mg to 40 mg of Zocor. One researcher stated that the new data points to the need for aggressive lipid-lowering treatments for people who have recently had a heart attack.